This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The prototypic synaptic scaffold PSD-95 associates with NMDA receptors (NMDARs) directly and AMPA receptors (AMPARs) indirectly, and is thought to regulate the localization and clustering of these receptors at the synapse. Despite extensive in vitro studies, the role of PSD-95 in the functional states of synaptic NMDARs and AMPARs in vivo remains elusive. The purpose of this project is to study the role of PSD-95 in synaptic transmission in the prefrontal cortex using a mouse strain lacking PSD-95.